Conventionally, as one example of a developing apparatus referred to above, there has been proposed an arrangement as disclosed in Japanese Laid-open Patent Publication No. 119159/1984. That apparatus includes a toner hopper having an agitating member, a roller arranged at an opening of the toner hopper so as to be driven for rotation thereof and a blade contacting the roller under pressure. Toner that is held in the toner hopper is transported based on rotation of said roller while the blade regulates the amount of toner. The roller directly transports toner held on the surface thereof to develop an electrostatic latent image on the surface of a photosensitive member, or after the roller transports the toner to a developing sleeve to be mixed and agitated with carrier, the roller transports it to develop the latent image.
However, in this type of developing apparatus, since after toner is held on the surface of the roller, an excessive amount of the toner is scraped off by the blade, preference is given to toner having a smaller grain diameter in the toner hopper. Thus, toner having a larger grain diameter is scraped off.
Therefore, while the toner is being consumed, some problems arise. Namely, as the residual amount of the toner in the toner hopper decreases, that is, as the number of sheets of copied paper increase, the texture of the image becomes rough, the fog of it produces, and besides spill of the toner increases.